Even if it is a good idea, it may not be relevant to a large company. For example, a business that makes $5 million/revenue a year is far too small for Facebook

Even if it is a good idea, it may not be relevant to a large company. For example, a business that makes $5 million/revenue a year is far too small for Facebook to care about, it's just a blip for them. Empirically Facebook is not starting 100s of tiny businesses a year, even though they have the personnel for it.